1. Field of the Invention
The present invention relates to a liquid crystal display that uses an organic layer and method of making the same.
2. Description of the Related Art
A liquid crystal display (“LCD”) comprises an LCD panel, a backlight unit, a driving part and a cover. The LCD panel includes a thin film transistor (“TFT”) substrate on which thin film transistors (“TFTs”) are formed, a color filter substrate on which color filters are formed, liquid crystals disposed between the TFT and color filter substrates and a sealant formed along the circumferences of both substrates to prevent leakage of the liquid crystals.
Lines such as gate lines, data lines and etc. are formed on the TFT substrate and a pixel electrode is disposed over the lines. A passivation layer is formed between the lines and the pixel electrode to insulate the lines and pixel electrode from each other. The passivation layer comprises an inorganic layer of silicon nitride (SiNx) or the like and is deposited on the lines by a chemical vapor deposition (“CVD”) method.
When the lines are close to the pixel electrode, cross talk is generated therebetween. Thus, an organic layer, instead of the inorganic layer, has been recently used to prevent the generation of cross talk. The organic layer is formed on the lines, not by the CVD method but, by a spin coating method, a slit coating method or the like, and thus the organic layer may thicken. Accordingly, the pixel electrode may be formed close to the lines or on the lines, thereby increasing an aperture ratio as well. Further, if the organic layer comprises material having a low dielectric constant, even generation of the cross talk decreases.
In the case of a transflective TFT substrate, the organic layer is used to form a lens part of a reflecting layer.
However, when a semiconductor layer contacts the organic layer, impurities from the organic layer badly affect the semiconductor layer, thereby deteriorating characteristics of the semiconductor layer. To solve this problem, an inorganic layer is formed between the semiconductor layer and the organic layer. In this case, however, more masks are needed to pattern both the inorganic layer and the organic layer. In particular, seven masks are used to make the transflective TFT substrate and six masks are used to make the transmissive TFT substrate, respectively.
When the organic layer is used as the passivation layer, the sealant is disposed on the organic layer. However, the organic layer and the sealant do not adhere to each other very well, thereby allowing the color filter substrate to easily separate from the TFT substrate.